Sports Bra Sizes: Complete Sizing Guide

Sports bra sizes combine band measurements with cup sizes or simplified sizing across support levels. This guide compares compression versus encapsulation styles, activity-specific support, and fit essentials to help you choose sports bras that perform during any workout.

Sports Bra Sizing Systems Comparison

Sports bras use different sizing systems from simplified S-M-L to traditional band and cup sizing.

Size (S-M-L) Band Size (inches) Cup Size Range Regular Bra Sizes
XS 30-32 A-B 30A, 30B, 32A, 32B
S 32-34 A-C 32A-C, 34A-C
M 34-36 B-D 34B-D, 36B-D
L 36-38 C-DD 36C-DD, 38C-DD
XL 38-40 D-DDD 38D-DDD, 40D-DDD
XXL 40-42 DD-G 40DD-G, 42DD-G

Support Levels by Activity Intensity

Sports bra support levels match workout intensity and impact to provide appropriate stabilization.

Support Level Activity Type Best For
Light Support Low-impact activities Yoga, pilates, walking, stretching
Medium Support Medium-impact activities Cycling, hiking, skiing, weight training
High Support High-impact activities Running, aerobics, HIIT, jumping, sports
Maximum Support Very high-impact, large cup sizes Marathon running, D+ cups, intense cardio

Compression vs Encapsulation Styles

Sports bras use two main support methods with different fit characteristics and ideal uses.

Style Type How It Works Best For Cup Size Range
Compression Presses breasts against chest A-C cups, slim fit, racerback styles A-C
Encapsulation Individual cups support each breast C+ cups, underwire or molded cups C-G+
Combination Compression plus separate cups All cup sizes, maximum support B-G+
Front-Zip Encapsulation with easy on-off Post-surgery, convenience, larger cups B-G+

Visual Sports Bra Style Comparison

Sports bra support styles from compression to encapsulation illustrated.

Sports bra style comparison Compression Encapsulation Combination Front-Zip

Sports Bra Size Calculator

Find your sports bra size based on regular bra measurements and activity level.

How to size sports bras correctly

Measure first, label second

Pick a tape measurement and match it to the chart. Labels (S/M/L, US/UK/EU numbers) drift between brands; the underlying body measurement does not. Use your underbust band measurement and a bust measurement at the fullest point. Sports bras run snugger than regular bras for support; sized too loose, they fail to do their job.

Picking between two sizes

Pick the smaller band size for low- and medium-impact bras (yoga, walking). Pick the larger band for high-impact (running) only if you experience chafing or rib soreness during use.

Brand and regional variation

The same labeled size can differ by a full size between brands and regions. Asian brands generally run a half size smaller than US brands; European brands fall in between. When in doubt, use the centimetre or inch measurement on the size chart, never the letter.

Common mistakes

  • Sizing by your old favourite without checking the new brand's chart.
  • Skipping the measurement step. Body shape changes; old numbers go stale.
  • Picking too tight in non-stretch fabrics — they don't break in the way leather does.
  • Trusting a single review's "runs small / runs large" without looking at the reviewer's measurements.